Add simplify function for LineString geometries based upon Douglas-Peucker algorithm

[chrismayer]

I have written a little patch (see attached file) for OpenLayers.Util in order to provide a function simplifying LineStrings. Base of the code is the Douglas-Peucker algorithm. Due to a threshold unnecessary vertices are removed.

I would be happy if this could be included to the code base of OpenLayers.

The code includes tests and an example showing he functionality.

Thanks for any review.

see  http://osgeo-org.1803224.n2.nabble.com/simplifyLineString-td5610746.html#a5610746

[ahocevar]

Thanks @chrismayer for this great patch. The implementation of Douglas-Peucker looks solid. Do you think you can modify your patch so this becomes part of OpenLayers.Geometry.LineString instead of OpenLayers.Util? I think simplify would make a nice name for this method.

[chrismayer]

Thanks ahocevar for your comments and reviewing!

I modified the patch (see attachment) that the simplify function is a part of OpenLayers.Geometry.LineString.

Thanks for reviewing again!

[ahocevar]

r10969

[marcjansen]

The example for the simplify-method references the old Util-method. The attached patch changes the example to be in accordance with the API.

[ahocevar]

@marcjansen: it's OpenLayers.Geometry.LineString::simplify, not OpenLayers.Layer.Vector::simplify

[marcjansen]

@ahocevar Ooops, sorry! Please check whether the next patch fits better.

[ahocevar]

r10973